Taste and depression from long covid

My brother has had depression and says he cannot taste food.He has lost 80 lbs in the last 5 years. He’s tried lots of medications for depression, has had ECT and magnetic therapy. He’s going to try spravado as soon as it gets approved by insurance co. Also I’ve read the nicotine patch may help with taste. Has anyone been dealing with these symptoms from the vaccine or from covid. It’s been 5 long years and trying to help my brother. He is 105 lbs and has been in and out of psychiatric hospitals and medical drs. No answers? Hoping to hear back. Thank you.